Railway signaling system



Nov. 30, 1937. PH. CRAGO 2,100,432.

RA ILWAY SIGNALING SYSTEM Original Filed June lO, 1956 g 5 ,3 10 $15? IA INVENTOR Paul H. 90

HIS ATTORNEY Patented Nov. 30, 1937 UNITED STATES PATENT OFFICE RAILWAYSEGNALING SYSTEM Paul H. Crago, Wilkinsburg, Pa, assignor to The UnionSwitch & Signal Company, Swissvale, pa a corporation of Pennsylvania Awe,

Original application June 10, 19.3.6, Serial: No. 84,498. Divided andthis application April 10, 1937, Serial- No. 136,118

6 Claims. (01. 246-46) means for causing, an approach lighted signal toshown disposed-above the associated roundels, but 5 display arestrictive indication when a train apit will; be readily understoodthat in actual pracproaches the signal if the filament of the lamp ticeeach. lamp will be located directly back of the for the signal next inadvance becomes burned out associated roundel, and will have associatedor broken. therewith a suitable optical system, not shown,

10 Other objects of my invention will appear as for projecting a beamoflight from the lamp. 1 the description proceeds. The signals Seachindicate proceed, stop, or,

The present application is a division of my cocaution according as the.roundel G, R, .or Y pending application, Serial No. 84,498, filed on isin front of the associated lamp L when this; June 10, 1936, for Railwaysignaling systems. lamp is lighted. Operatively'connected with each Iwill describe one form of railway signaling armature 5 is a circuitcontroller comprising two 1 system embodying my invention, and will thenmovable contact fingers land 8. The movable point out the novel featuresthereof in claims. contact finger? cooperates with a fixedcontact 1e Theaccompanying drawing is a diagrammatic toolose a contact '!''l when: thearmature 5pc:- view showing one form of signaling system emcupies itsright-hand extreme position, and with bodying my invention. a fixed:contact lto close a contact l-l when Referring to the drawing, thereference characthe armature occupies its interm d a e po ters I and ldesignate the track rails of a stretch or its left-hand extremeposition; While themovof railway track along which traflic normally ablecontact finger 8 cooperates with a fixed conmoves in the directionindicated by the arrow. tact 8 to close a contact 8-8 when the arma-These track rails are divided, bymeans. of insuture occupies itsleft-hand extreme position, and 25,

lated joints 2, to form blocks, only one of which, with a fixed contact6- to close a contact 8 -8 AB, is shown complete in the drawing; Eachwhen the armature occupies its intermediate or'." block. is providedwith a track circuit comprising its right-hand extreme position. Asignal ofthe atrack relay, designated by the reference charactypedescribed is disclosed and. claimed in Letters ter TR with a suitabledistinguishing exponent, Patent of the United States No. 1,864,224,granted and connected across. the rails adjacent one end to Wesley B.Wells, on June 21, 1932, for Light of the section, and a suitable sourceof track cir- S nals. cuit current, hereshown as atrack battery 3, con-Associated with each signal is a slow-releasing nected across the railsadjacent the other end of Signal repeater el y designated y reference35. the section. character SR. witha suitable distinguishing ex Locatedadjacent the entrance end of each ponent, an approach lighting relaydesignated by block is a signaldesignated by the reference charthereference character ALR with a suitable disactor s with an exponentcorresponding to the tinguishing exponent, andasl w-releasing lihtlocation. Each signal, as here shown, is of the out relay designatedby the reference character 4 type commonly known as: a searchlightsignal, and 'LOR with a suitable distinguishing exponent. 40 comprisesan armature 5 mounted to rotate be- Each lightout relay LOR is providedwith two tween an intermediate position to which it is windings, one ofwhich, 9, has a sufiiciently high biased, and two extreme positions.Each armaresistance so that when this winding is connected ture 5. iscontrolled by an armature winding 6, in series with the filament of thelamp L ofthe.

and is polarized by the field from a permanent associated signal in. achecking circuit for the 45 magnet or an electromagnet (not shown) insuch lamp presently to be described, the lamp will, not manner that whenthe winding 6' is energized, the become lighted, and the other of which,It, has a armature will rotate to its right-hand or leftsnfficlently lowresistance so that when this wind: hand extreme position according aswinding 6 is ing is connected. in series with the filament of the thensupplied with current of normal or reverse lamp L of the associatedsignal in an energizing polarity, respectively. Attached to eacharmjacircuit for the lamp presently to be described, ture 5 to rotatetherewith are three colored the lamp will become lighted. roundels G, R,and Y, which are arranged to be Each signal repeater relay is providedwith disposed in the path of abeam of light projected two energizingcircuits which are controlled by r from an associated lamp L accordingas the the circuit controller of the associated signal.

My invention relates to railway signaling systems of the type involvinglight signals which are approach lighted.

One object of my invention is to provide novel extreme position,respectively. For convenience in illustration, each lamp L in, thedrawing is advance.

when track relay TR and lightout relay LOR Referring to relay SR forexample, the one energizing circuit for this relay is closed when andonly when signal S indicates proceed, and passes from terminal X of asuitable source of current not shown in the drawing through contact ofsignal S wires 24 and 25, and the winding of relay SR to terminal Theother energizing circuit for relay SR is closed when and only whensignal S indicates caution, and passes from terminal K through contact'!l of signal S wire 32, contact 8-8? of signal S wire 25, and thewinding of relay SR to terminal 0. It will be apparent, therefore, thatrelay SR will be energized when signal S occupies either'its proceed orits caution position, but will be deenergized when signal S occupies itsstop position. Relay SR is made sufficiently slow releasing so that itwill not open its front contacts while signal S is moving from itsproceed to its caution position, or vice-versa.

' The winding 6 of each signal is controlled by the associated track andlightout relays and by the signal repeater relay for the signal next inadvance, through the medium of a polarized line circuit which includesthe winding of the approach lighting'relay for the signal next in 7Referring to signal S for example,

are both energized, and signal repeater relay SR is also energized, thepolarized line circuit for winding 6 of signal S is closed,and underthese conditions, winding 6 is supplied with cur rent of normalpolarity, the path of the current being from terminal X through thewinding of relay ALR wire I2, front contact !-l3 of relay SR line wirel4, front contact 15 of track relay TR wire 56, front contact ll oflightout relay LOR wire 18, winding 5 of signal S wire l9, front contact2i! of track relay TR line wire 2|, front contact 22--22 of signalrepeater relay SRB, and wire 23 to terminal 0. When track relay TR andlightout relay LOR are both energized and signal repeater relay SR isdeenergized, the polarized line circuit for winding 6 of signal S isagain closed, but under these conditions, dueto the fact that the backcontacts l3' l3 and 22-42 of relay SR) are then.

closed instead of the front contacts |3--l3 and 22-42 winding 6 ofsignal S is supplied with current of reverse polarity over this linecircuit. When either track relayTR or lightout relay LOR is deenergized,the polarized'line circuit for winding 5 of signal S will, of course, beopen.

It will be apparent, therefore, that when track relay TR and lightoutrelay LOR are both energized," the mechanism of signal S will occupy itsproceed orits caution positionaccording as signal repeater relay SR isthen energized or deenergized, but that, when either track relay TR. orlightout relay LOR is deenergized, the mechanism of signal S will occupyits stop po-' sition. It will also be apparent that approach lightingrelay ALP?) will be energized whenever winding 6 of signal S isenergized by current of either normal or reversepolarity, but that, whenwinding 5 of signal S is deenergized, ap-

proach lighting relay ALR 'will also be deener- 'gized.

Each signal lamp L is provided with an energizingi circuit which iscontrolled'by the associated' signal repeater and. approach lightingrelays in such manner that this circuit will become closed when eitherof these relays becomes deenergized, and which includes the lowresistance winding of the associated lightout relay. Each and 21, backcontact 28 of relay SB connected in multiple with back contact 29 ofrelay ALR wire 3!], winding it of relay LO-R and wire 3| to terminal 0.The checking circuit for lamp L passes from'terminal X through thefilament of lamp L wire 26, resistor R and the winding 9 of lightoutrelay LOR to terminal 0. The parts are so proportioned that lamp L willbecome lighted when and only when the energizing circuit for the lamp isclosed, but that, relay LOR will hold its front contacts closed wheneither the energizing or the checking circuit for lamp L is closed.

It should be pointed out that while, as shown I in the drawing, eachchecking circuit includes a associated lamp from becoming incandescentwhile the checking circuit in which the resistance is included is closedand the associated energizing circuit is open; It should also be'pointedoutthat when the energizing circuit for a lamp is closed, the checkingcircuit is also closed, so that the current which is supplied to thelamp flows through the windings 9 and ill of the associated lightoutrelay in parallel. The windings 9 and II] are so arranged that thefluxes set up in the relay when both of these windings are energized arecumulative.

As shown in the drawing, all parts are in their normal positions, thatis to say, all relays are picked up, the winding 6 of each signal issupplied with current of normalv polarity, so that the armatures 5 or.signals S and S both occupy their right-hand or proceed positions, andthe lamps L and L are both extinguished.

Inexplaining the operation of the apparatus as a whole, I will firstassume that a train moving in the direction of the arrow traverses thestretch oftrack shown in the drawing. When the train enters the block inrear of block A-B, theshunting of the track relay associated with thisblock' will cause approach lighting relay ALR to become deenergized andclose its back contact 29. The closing of this contact will complete theenergizing circuit for lamp L and this lamp will therefore becomelighted and will cause signal S to display a proceed indication.

When the train enters block A-B, track relay TR will become deenergized,and will interrupt the circuit for'winding 6 of signal S, thuscausingthe mechanism of this signal to move to its which was previously closedfor signal repeater relay SB and since both circuits for this relay willthen be open, this relay will become deener gized. The deenergization ofrelay SR will cause.

the polarity of the current supplied to the circuit for the winding 6 ofthe signal for the block to the rightfof block AB'to become closed, andas a result, as soon as the train moves out of this block, thissignalwill move to its caution position. The deenergization of relay SRwill also cause this relay to complete, at its back proach lightingrelay ALR picks up'due to the train having passed out of the block tothe right of block AB, signal S will continue to display Thedeenergization of apa stop indication. proach lighting relay ALlR. willcause the energizing circuit for lamp L of signal S to become closed,and this lamp will therefore become lighted, thus causing signal S todisplay a proceed. indication. K

When the train enters the block to the left of block AB, track relay TRwill become deenergized and will cause winding 5 of signal S to becomedeenergized. The deenergization of winding 6 of signal S will cause themechanism of this signal to move to its stop position, which movement,in turn, due to the resultant operation of the associated circuitcontroller, will deenergize signal repeater relay SR When relay SRbecomes deenergized, it will reverse the polarity of the currentsupplied to the circuit for winding 5 of signal S but as long as anypart of the train remains in block A-B, the circuit for winding 6 willremain open at the front contacts of track relay'TR and signal S willcontinue to display a stop indication. As soon, however, as the trainpasses completely out of block AB,

' the resultant energization of track relay TR will complete the circuitfor winding 6 of signal S and this signal will then move to its cautionposition. The movement of signal S to its caution position will completethe previously traced circuit for signal repeater relay SB includingcontacts and 83 of the circuit controller of signal S and relay SR willthen pick up.

When this relay picks up, it will interrupt the energizing circuit forlamp L and will cause the winding 6 of the signal for the block totheleft of block AB to be supplied with current of normal polarity,whereupon the mechanism of this signal will move to its proceedposition.

When the train leaves the block to the left of block A-B, track relay TRwill pick up and will cause signal S to move to its caution position inthe same manner that the picking up of track relay TR caused signal S tomove to its caution position. As soon as signal S reaches its cautionposition, signal repeater relay SR will pick up, whereupon signal lamp Lwill become extinguished, and the mechanism for signal S will move toits proceed position. When the train passes out of the second block inadvance of block AB, signal S will move to its proceed position, and allpartswill then be restored to the positions in which they are shown inthe drawing.

I will now assume that with the parts in the positions in which they areshown in the drawing, the filament of lamp L becomes brokernand that atrain subsequently'enters the block to the right of point A. When thefilament of lamp L becomes broken, the checking circuit for this lampbecomes interrupted at the lamp filament, and lightout relay LOB.therefore becomes deenergized, and opens its front contact H. Theopening of this front contact will deenergize the winding 6 of signal Swhereupon the signal mechanismof this signal will move to its stopposition. When the mechanism of signal S moves to its stop position,signal repeater relay SR will become deenergized, and will reverse thepolarity of the current supplied to winding 6 of signal S thus causingthe mechanism of signal S to move to its caution position. As a result,when the train enters the, block to the right of point A and causesapproach lighting relay.

ALR to-become deenergized and complete "the circuit for lamp L signal Swill indicate caution even though neither of the two blocks in advanceof point A is occupied.

Ii' signal S occupies its caution position instead of its proceedposition when the filament of lamp L becomes broken, and a trainsubsequently enters the block to the right of point A, the operation ofthe apparatus will be similar in all respects to that just described. Itwill be seen, therefore, that with a signal system constructed in themanner described, if the filament of a signalslampbecomes broken whenthe mechanism of the si nal in the rear occupies its proceed position,the mechanism of thesignal in the rear:

become lighted due to the presence of a train in the block immediatelyinrear of thesignahboth the checking andenergizing circuits for the lampwill become open, .andthe associated 'lightout:

relay will become deenergized, and will thuscause i the signal mechanismto move to itsxstop position;

This is desirable because since the operating rules of railroads usuallyrequire that a dark signal be obeyed as a stop signal, and since thesignal mechanism occupies its stop position, if any light from anextraneous source such, for example, as a locomotive headlight orth-esuns rays when the sun is close to thehorizon, should enter the signaland be reflected back by the optical assembly or" the signal, theresulting phantom indication would be a stop indication. The signalmechanism, after being moved to its stop position in the manner justdescribed, will subsequently remain in its stop position until theburned out lamp is replaced, and the-signal next in rear will beprevented from moving to it's proceed position,

even though trafiic conditions in advance are such that the mechanism ofthis signal would normally assume its proceed position.

Although I have herein shown and described only one form of railwaysignaling system embodying my invention, it is, understood that vari- 2one changes and modifications may be made therein within the scope ofthe appended claims without departing from the spirit and scope of myinvention, a

Having. thus described my invention, what I claim is: i

1. In combination, a stretch of railway track 7 divided into blocks, arelay associated with each block, each said relay having two windings, asignal for each block controlled by traffic conditions in advance and bythe associated relay and includinga lamp which at times becomes lightedto cause the signal to display an indication, a constantlyclosedcheckingcircuit for each lamp including the one winding of theassociated relay and effective for energizing the associated relay butnot for energizing the associated lamp, and means effective when a trainapproaches a signal for connecting the other winding of the associatedrelay in parallel with the one Winding 2.'In combination, a stretch ofrailwaytrack divided into blocks, a relay associated with each block,each said relay having a high resistance and a low resistance winding, asignal for each block controlled by traffic conditions in advance and bythe associated relay and including a lamp which at times becomes lightedto cause the signal to display an indication, a constantly closedchecking circuit for each lamp including the high resistance winding ofthe associated relay and effective for energizing the associated relaybut not for energizing the associated lamp, and means effective when atrain approaches, a signal for connecting the low resistance winding'ofthe associated relay in parallel with the high resistance winding tothereby cause the signal lamp to become lighted.

3. In combination, a stretch of railway track divided into blocks, atrack circuit for each block including a track relay; a signal for eachblock capable of assuming a proceed, caution, or stop position accordingas the signal mechanism is supplied with current of normalpolarity,reverse polarity or is deenergized, each said signal including a lampwhich at times becomes lighted to cause the signal to display anindication; a'signal repeater relay controlled by each signal andarranged to be energized at all times except when the signal occupiesits stop position, a lightout relay for each signal having two windings,an approach lightingrelay for each signal; an energizing circuit foreach signal mechanism including a front contact of theassociatedlightout relay, a front contact of the track relay for theassociated block, pole changing contacts of the signal repeater relayfor the signal next in advance and the winding of the approach lightingrelay for the signal next in advance, the parts being so proportionedthat each signal energizing circuit will contact of the associatedapproach lighting relay and a back contact of the associated signalrepeater relay in multiple. l

4. In combination, a stretch of-railway track divided into blocks, atrack circuit for each block 7 including a track-relay; a signal foreach block capable of assuming a proceed, caution, or stop positionaccording as the signal mechanism is supplied with current of normalpolarity, reverse polarity or is deenergized, each said signal includinga lamp which at times becomes lighted to cause the signal to display anindication; a signal repeater relay controlled by each signal andarranged to be energized at all times except be supplied with current ofnormal or reverse with the one winding of such relay over a back whenthe 'sig'naloccupies its stop position, a lightout-relay forleachsig nalhaving a high resistance and a lowresistance winding, an approachlighting relay for each signal; an energizing circuit for each signalmechanism including a front contact of the associated lightout relay, afrontcontact of the track relay for the associated block, pole changingcontacts of the signal repeater relay for the signal next in advance andthe winding of the approach lighting relay for the signal next inadvance, the parts being so proportioned that each signal energizingcircuit will be supplied with current of normal or reverse polarityaccording as the signal repeater relay which controls it is picked up orreleased, and that each approach lighting relay will be picked upwhenever the signal energizing circuit in which it is included isclosed; a constantly closed checking circuit for each lamp including thehigh resistance winding of the associated lightout relay and effectivefor energizing the associated lightout relay but not for energizing theassociated lamp, and another circuit for each lamp including the lowresistance windings of the associated relay connected in parallel withthe high resistance winding of such relay over a back contact of theassociated approach lighting relay and a back contact of the associatedsignal repeater relay in multiple. 7

5. In combination, a stretch of railway track divided into blocks, a twowinding relay associated With each block, a signal for each block con-.trolled by the associated relay and by traffic con-. ditions'in advanceand including a lamp which at times becomes lighted to cause the signalto display an indicatioman energizing circuit for each lamp controlledby traflic conditions in rear of the associated signal and including onewinding of the associated relay, and a constantly closed checking.circuit for the lamp including the other winding of the associatedrelay.

6. In combination, a stretch of railway track divided into blocks, asignal for governing the entrance of traific into each block including awinding and a lamp and responsive to reversals in the polarity ofthecurrent supplied to the winding, a track circuit for each blockincluding a track relay, a slow-releasing signal'repeater relay foreachsignal energized whenever the winding of theassociated signal isenergized, a lightout relay for each signal having a low resistance winding and a high resistance winding; a polarized line circuit for eachsignal including the winding of the signal, a front contact of theassociated lightout relay, airontco'ntact of the associated associatedapproach lighting-relay, anda constantly closed checking circuit foreach lamp including the high resistance winding of the associatedlightout relay.

7 PAUL H. CRAGO.

track relay, pole-changing contacts of the signal repeater relay for thesignal next in advance and

